Method of regulating CSF drainage

Abstract

An implantable drainage device for draining the cerebro-spinal fluid of a patient, the device including:a drainage valve including a valve member and a valve seat;a control unit suitable for modifying an operating parameter of said valve, at least as a function of a measurement (D) of the fluid flow rate through said valve;an actuator controlled by the control unit, suitable for modifying the operation of said valve as a function of said operating parameter as modified by the control unit; anda mass flowmeter suitable for evaluating said flow rate of fluid through said valve.

Description

[0001]The invention relates to an implantable drainage device for draining the cerebro-spinal fluid (CSF) of a patient, and it also relates to methods of implementing the device. Such a device is intended in particular for treating hydrocephalus. It serves to shunt the cerebro-spinal fluid contained in the ventricles in the cranial cavity to some other site for resorption, e.g. the peritoneal cavity.BACKGROUND OF THE INVENTION[0002]Conventionally, a drainage device comprises a drainage valve presenting operation that is modifiable as a function of a measured pressure difference, as described in DE 196 54 990. The pressure difference must then be measured between the inlet and the outlet of a very narrow passage of small diameter, thereby specifically running a major risk of the passage becoming obstructed. Furthermore, a pressure difference sensor generally presents problems of stability and of drift over time.[0003]Also, international application WO 2006 / 115724 discloses an implant...

AI Technical Summary

Benefits of technology

[0015]This makes it possible to limit the energy consumption of the flowmeter.

[0043]Adjusting the operating parameter serves in particular to modify the rate at which cerebro-spinal fluid is evacuated through the drainage valve, and as a result to modify the volume of cerebro-spinal fluid that is evacuated through the drainage valve.

[0055]This type of control serves in particular to avoid excessively increasing the flow rate of cerebro-spinal fluid, in particular in the event of the patient changing position or during periods of paradoxical sleep.

[0080]Powering the flowmeter and / or the control unit and / or the actuator intermittently, and in particular solely during drainage stages, serves in particular to greatly reduce energy consumption.Without a Regulator

[0094]During the monitoring stage, it compares the mean flow rate (total volume of cerebro-spinal fluid that has been evacuated since the previous monitoring stage divided by Δt, where Δt represents the time between two monitoring stages), and compares it with the setpoint flow rate D*. The regulator then adjusts the opening frequency F0 and / or the bolus duration tb so as to reduce any difference between the setpoint flow rate D* and the mean flow rate evacuated up to the following monitoring stage.Permanent Drainage Mode

[0102]Whatever the intended drainage mode, the control unit may be configured so as to trigger so-called “calibration stages” e.g. at regular intervals, preferably once every hour, more preferably once every day, still more preferably once every month, thereby enabling the setpoint flow rate D* to be corrected.

Problems solved by technology

The pressure difference must then be measured between the inlet and the outlet of a very narrow passage of small diameter, thereby specifically running a major risk of the passage becoming obstructed.

Furthermore, a pressure difference sensor generally presents problems of stability and of drift over time.

Nevertheless, that flowmeter is not used in association with a device that enables the opening conditions of a drainage valve to be modified.

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